Low-cost and large-scale preparation of ultrafine TiO₂@C hybrids for high-performance degradation of methyl orange and formaldehyde under visible light

Developing high-efficiency and low-cost visible light photocatalyst is a great challenge for degrading both air and liquid pollutants. Herein, we developed a large-scale preparation of ultrafine TiO2@C hybrid visible light photocatalyst for high-performance degradation of formaldehyde and methyl orange (MO) at low cost using the ultra-low temperature (<200?) air calcination method. The as-designed TiO2@C hybrids are at the scale range of 2-5 nm and modified by ultrafine carbon layers enabling the strong physical adsorption and narrowing the corresponding band gap. Specifically, the photocatalytic performance of TiO2@C hybrids for formaldehyde and MO degradation was investigated both in the air and liquid pollutant. After optimization, the TiO2@C hybrid obtained at 175? possesses relatively better photocatalytic degradation performance than other parallel control composites under visible light irradiation. The enhanced photodegradation ability of TiO2@C-175? hybrid with visible light response attributes to novel hybrid structure with rich defect active sites and narrow band gap (2.51 eV), favoring dual functions of physical adsorption and chemical degradation. This ultra-low temperature air calcination approach can open a low-cost and scalable pathway to design TiO2@C hybrids for green environment.